Optically clear pressure sensitive adhesives (OCAs) are finding wide applications in optical displays. Such applications include bonding polarizers to modules of a liquid crystal display (LCD) and attaching various optical films to a glass lens in, for example, mobile hand held (MHH) devices. During use, the display can be subjected to various environmental conditions, such as high temperature and/or high humidity.
It has been observed that OCAs can exhibit a cloud point, (turn hazy/“white”) after subjecting optical laminates of optical films and OCAs to high temperature/humidity accelerated aging tests and subsequently cooling the laminates down to ambient conditions. While still hot, the laminates may be perfectly clear, even when saturated with moisture. But upon cooling they can exhibit a cloud point and turn hazy or “white”. Frequently, the haze will disappear over time upon storage of the laminate under ambient conditions. The haze disappearance can often be accelerated by gently heating the optical laminates.